Lo,
everytime when I call select hibernate query (via CreateQuery(select...etc.) ) my apl start to perform SQL query over the db. It would be ok if the data in db would be changed, but if they don't I need my apl to read these data from memory (apl -> DataTable -> DataAdapter -> DB style) due performance issue. I guess Hibernate should can do this. Probably there is some construction in my code which brake this function. Do you know appropriate way how to use Hibernate to reach this functionality?

Thanks a lot for your response...

If I understand you correctly, you want NHibernate to not call the database every time you issue the same query.
NHibernate has support for this via query caching.
This requires three things:
1/ enable the second level cache
2/ enable query caching
3/ on a query that you want to be cache, call SetCachable(true)